Various entities, such as search providers, on-line retailers, financial institutions, research laboratories, universities, and other computing-intensive organizations often conduct operations from large scale computing facilities, sometimes referred to as data centers or, more colloquially, “server farms.” Such computing facilities house a large number of servers along with network and computer equipment to process, store, and exchange data as needed to execute desired functionality. Such functionality typically includes the storage, processing, and retrieval of data. Typically, such a server farm includes many server racks. In some cases, there can be hundreds, or even thousands of racks. Each server rack, in turn, includes many servers and other associated computer equipment.
Computer systems typically include a number of components that consume power. Such components include printed circuit boards, mass storage devices, networking interfaces, and processors. Given the precise and ever-increasing power requirements demanded by these components, reliable and efficient power delivery is crucial for successful operation of such server farms. Additionally, in some cases the reliability and availability requirements of the data center infrastructure must meet or exceed predetermined statutory requirements, as demonstrated by many financial institutions, for example. Further, as is the case for financial institutions as well as healthcare organizations, educational organizations, and retail organizations, other statutory requirements demand that certain standards be met to ensure the protection of personal customer data. The statutory requirements often place stringent safeguards on the physical and technical security of personal data.
Because of issues such as availability, reliability, job load, and other organizational requirements of data centers, additional infrastructure requirements must be met. For example, the issue of effectively cooling a data center (i.e. the removal of excess heat) is a critical issue which must be addressed to ensure stable and reliable operation of the center. Each of the many devices in the data center generates substantial amounts of heat, whether the device is a server, a blade, a switch, a backup unit, a communications unit, or another device. In fact, the issue of cooling modern data centers has become such an important design criterion that it directly impacts the layout and design of the center. For example, some data centers are arranged in so called “hot rows” and “cold rows,” where equipment generating excess heat is grouped together in “hot rows” and surrounded by rows of cooler-running equipment grouped in “cold rows,” named for their ability to serve as heat sinks, absorbing some of the excess heat from the “hot” equipment. Other centers are designed with cooling devices placed adjacent to particularly hot devices, with the cooling devices including fans, air conditioning units, water cooling systems, and so on. Another significant data center design consideration involves providing sufficient power to the data center. Particularly in the case of high-reliability data centers, power can be provided by more than one power grid to provide redundancy, while for other data centers, power can be provided by a combination of a power grid and locally generated power. Regardless of how the power is provided to the data center, providing reliable and efficient power to the large number of computers and associated equipment in modern data centers or server farms is an important aspect of successful operation of such facilities.